WASHINGTON — There is a 45-year-old Democrat from the Rust Belt who has hosted yoga sessions on the Capitol lawn, a 40-year-old Harvard-educated former Marine from Massachusetts who made recruiting and supporting veterans to run for Congress a pet cause, a few seasoned lawmakers who rarely buck their party, and a handful of newcomers who campaigned promising change in Washington.
The 16 House Democrats who signed a letter on Monday calling for new leadership of their party are the leading edge of what threatens to escalate into a full-blown intraparty fight for control of the new majority. The letter was an unmistakable message to Representative Nancy Pelosi of California that she may not have the votes to reclaim the speakership she lost in 2011.
Their ideological leanings and political profiles are diffuse — certainly not the Democratic equivalent of the Freedom Caucus, the group of ultraconservative Republicans that often acts as a thorn in the side of G.O.P. leadership. What the group shares is a determination to shake up the top echelons of the House Democratic Caucus, whose leaders have remained unchanged for more than a decade, with Ms. Pelosi, 78, at the helm; Representative Steny H. Hoyer of Maryland, 79, as the No. 2, and Representative James E. Clyburn of South Carolina, 78, as the third ranking.
So far, no lawmaker has been willing to come forward to challenge any of them directly, and the list of signatories to the letter is limited, representing fewer than 10 percent of House Democrats. In fact, their ranks may be shrinking as Ms. Pelosi pulls them to her one at a time. On Wednesday, one of their most senior members, Representative Brian Higgins from Buffalo, dropped out and endorsed Ms. Pelosi.
Here are some of the people leading the charge.
The original rebel: Representative Tim Ryan of Ohio
CreditAllison Farrand for The New York Times
After the 2016 election left Democrats wringing their hands about white working-class voters, Mr. Ryan challenged Ms. Pelosi for the minority leader’s job. He lost but drew 63 votes, a significant number of Democrats willing to say publicly that they wanted someone new on top.
Since then, Mr. Ryan, 45, who represents the blue collar steel town of Youngstown, has continued to build a national profile as a different sort of Democrat, one who believes his party’s brand is foundering and its leaders must do more to appeal to white working-class voters who have abandoned the party.
He made it his business over the past two years to cultivate a crop of Democratic candidates who campaigned as change agents, promising their constituents they would not back Ms. Pelosi for speaker if they won and landed in the House majority.
“We have an obligation to help them keep their word,” Mr. Ryan said. “These members said in their campaigns they wouldn’t vote for Leader Pelosi. Where we come from, when you make promises to your constituents, you should keep them.”
But Mr. Ryan is no conservative Democrat in the mold of that vanished breed. A yoga and meditation enthusiast, he wrote a book on mindfulness and has recently moved left on issues like abortion rights and gun safety.
Allies of Ms. Pelosi have accused Mr. Ryan and his fellow rebels of launching a sexist attack on the nation’s first woman speaker, branding their movement with the hashtag #FiveWhiteGuys. Mr. Ryan did little to help himself by responding that there were “plenty of really competent females” who could take on Ms. Pelosi and win.
“This is politics in 2018, people can do what they want,” Mr. Ryan said last week, declining to comment on the criticism. He said he was encouraging Representative Marcia Fudge of Ohio, 66, to run for speaker, “and I think that speaks for itself.”
Then on Tuesday, Ms. Fudge withdrew her name from consideration after Ms. Pelosi created a new subcommittee on voting rights — and put Ms. Fudge in charge of it.
The veteran: Representative Seth Moulton of Massachusetts
Mr. Moulton has always styled himself as a disrupter in Congress. He won his seat in 2014 after challenging a long-serving Democrat, Representative John Tierney, in a primary, toppling a lawmaker who had served almost 20 years but was running under an ethical cloud.
Now, Mr. Moulton, 40, who supported Mr. Ryan in his 2016 challenge to Ms. Pelosi, has taken his change argument national, saying Democrats need new leaders to reflect a new party. A Harvard-educated former Marine who served four tours in Iraq and earned the Bronze Star, Mr. Moulton has made it a priority to recruit and support veterans to run for office. He formed a political action committee and traveled extensively to boost them during the 2018 campaign, and many of them declared they would not vote for Ms. Pelosi.
“The American people chose them out of a desire for real change and new leadership in Washington,” Mr. Moulton wrote Tuesday in an op-ed on CNN’s website. “And if we, as Democrats, are going to answer that call, we can't turn around and choose the same leadership we've had in place since 2003.”
Mr. Moulton’s effort has stirred Democratic ire. When he returned to his northeastern Massachusetts district this week for Thanksgiving, a crowd of angry constituents heckled him at a town hall. He appeared to take the blowback in stride, saying it was “important for me to hear your feedback and engage with your questions.”
The trailblazer: Representative Kathleen Rice of New York
It was Ms. Rice who distributed the letter on Monday; she has become the public face of the insurgency after accusations of sexism by Ms. Pelosi’s allies. She was also the first Democrat to come out in public support of Mr. Ryan’s challenge to Ms. Pelosi two years ago.
“There’s no question that this election had everything to do with voters wanting change, they wanted a next generation of Democrats to lead the way,” Ms. Rice, 53, said last week.
An outspoken supporter of Mr. Ryan’s earlier challenge of Ms. Pelosi, Ms. Rice, a former career prosecutor, said that as a candidate she wanted to bring political independence to Washington and to break the partisan gridlock that had soured the public on Congress.
Since arriving, she has been vocal about her belief that Democrats needed new leaders to improve an image that was no longer serving the party, and that Ms. Pelosi — vilified endlessly by Republicans as a San Francisco “limousine liberal” — was part of the problem.
“I think it’s my job to speak truth to power,” Ms. Rice said. “It’s very difficult to do, but I can tell you in the quiet of meetings, a lot of people agree with what I’m saying.”
The freshman: Representative-elect Jeff Van Drew of New Jersey
Mr. Van Drew is one of five newly elected freshmen who have signed onto the letter, following through on pledges they made during their campaigns not to back Ms. Pelosi. Other members-elect who made the same promise, such as Mikie Sherill of New Jersey and Abigail Spanberger of Virginia, have opted not to sign, although they say they still do not plan to support her.
Mr. Van Drew, 65, is a fiscally conservative “Blue Dog” from New Jersey who has voted against gay marriage and a series of gun control measures in New Jersey’s State Senate, and flipped his district from Republican for the first time in two decades. Having been branded a “Pelosi liberal” by his opponent, Mr. Van Drew campaigned vowing not to vote for the California Democrat, saying he would instead seek out a fresh-faced healer.
“I’ve made my commitment,” he said recently. “I’ve been willing to express that openly and others have as well, which is not necessarily a position I wanted to be in originally,” he added. “But I do keep my word.”
The insider: Representative Linda Sánchez of California
Ms. Sánchez is the only member of the dissident group who is currently serving in leadership, as the vice chairwoman of the Democratic Caucus, the fifth-ranking position. When she told C-Span last year that it was time for Ms. Pelosi and other top House Democrats to “pass the torch to a new generation of leaders,” it was seen as a rare display of disloyalty from Ms. Pelosi’s inner circle, and one that could doom her future prospects in the party.
Ms. Sánchez, 49, the daughter of Mexican immigrants who has represented a suburban Los Angeles district for 15 years, is the third-ranking Latina in Congress and a former chairwoman of the Congressional Hispanic Caucus. A labor lawyer and civil rights leader before she arrived in Washington, Ms. Sánchez served for several years alongside her sister, former Representative Loretta Sánchez, making history as the first pair of sisters to serve together in Congress.
Like her older sister did, Ms. Sánchez stands out in the stodgy corridors of the Capitol for her edgy style — she dyed the tips of her bobbed brown hair a hot pink last year, and once skirted House rules to paint the walls of her office bright orange — and her irreverent sense of humor. (She was named the “Funniest Celebrity in Washington” in 2006.)
She also established herself as a trusted lieutenant of Ms. Pelosi, landing an influential post as the ranking Democrat on the Ethics Committee and a seat on the high-profile House Select Committee on Benghazi.
Ms. Sánchez had planned to seek a promotion this fall, announcing she was running for chairwoman of the caucus, the No. 4 spot. But she withdrew from the race earlier this month after her husband was indicted on federal charges of conspiracy and theft.
The un-maverick: Representative Ed Perlmutter of Colorado
Mr. Perlmutter is no rabble-rousing upstart trying to get a foothold in a seniority-driven House. He rode into Congress on the Pelosi-led Democratic wave of 2006 with an easy victory in a suburban Denver district that had been held by Republicans. A former state senator, Mr. Perlmutter was a seasoned lawmaker and was for most of his Washington career a fairly reliable ally of the leadership. Not so any more.
“There are some of us who think we need a change in our leadership,” Mr. Perlmutter said in an interview. “I didn’t hide that in ’16. I still think that.”
The congressman ran on a message of “Perlmutter for Change” in 2006 and wants to follow through on that theme.
“This gives me no pleasure,” he said of being part of the opposition to Ms. Pelosi and her top lieutenants. “They are all my friends and they have all helped me, but sometimes you have to tell your friends what they need to hear.”
Carl Hulse and Catie Edmondson contributed reporting.